Photography dry copying process with a merocyanine dye

ABSTRACT

CERTAIN MEROCYANINE DYES MAKE IMPROVED SENSITIZERS FOR LIGHT-SENSITIVE PHOTOGRAPHIC LAYERS CONTAINING THE SENSITIZER AND AN IMAGE-PRODUCING COMPOUND CAPABLE OF TRANSFER AT 80-200*C. TO AN IMAGE-RECEIVING LAYER IN CONTACT WITH THE PHOTOGRAPHIC LAYER, BUT RENDERED NONTRANSFERABLE WHERE EXPOSED TO LIGHT.

United States Patent Office 3,764,322 PHOTOGRAPHY DRY COPYLN G PROCESS WITH A MEROCYANINE DYE Helmut Kampfer, Cologne, Johannes Gotze, Berg, Amta von Konig, Leverkusen, and Hans Ohlschlager, Cologne, Germany, assignors to Agfa-Gevaert Aktieugesellschaft, Leverkusen, Germany No Drawing. Filed Aug. 25, 1971, Ser. No. 174,929 Claims priority, application Germany, Aug. 27, 1970, P 20 42 531.4 Int. Cl. G03c 5/54 US. Cl. 96-29 D 32 Claims ABSTRACT OF THE DISCLOSURE Certain merocyanine dyes make improved sensitizers for light-sensitive photographic layers containing the sensitizer and an image-producing compound capable of transfer at 80200 C. to an image-receiving layer in contact with the photographic layer, but rendered nontransferable where exposed to light.

The present invention relates to a photographic dry copying process and to a light sensitive material for carrying out this process.

Dry photographic processes for producing copies of an original are already known. The photographic materials used are mainly materials which contain layers sensitive to light or to heat. These layers are exposed imagewise to light or heat to initiate a color forming reaction which results in formation of the image.

The known light sensitive materials of the type mentioned above which can be used for producing negative copies of images have, however, numerous disadvantages, including the fact that their sensitivity to light is insuflicient, especially in the visible region of the spectrum, so that the copying times required are too long and the reproduction of colored originals is difiicult. Moreover, the produced images are still sensitive to light and generally they can only be stabilized against daylight by a very complicated aftertreatment.

Other processes for the production of copies are also known which involve imagewise exposure of a light sensitive layer which contains a light sensitive compound and an image producing compound which can be transferred to an image receiving layer, the image producing compound in the exposed areas being converted into a nontransferable compound. The exposed layer is then contacted with an image receiving layer which contains compounds which react with the image producing compound to form colored compounds, and the layers which are in contact with each other are heated to a temperature at which the image producing compound from the unexposed areas of the light sensitive layer is transferred to the image receiving layer.

These prior processes include for example the so-called heat development processes in which light sensitive materials are used which comprise a silver halide emulsion layer and contain a photographic developer substance. After exposure to light, the photographic material is developed by heating in contact with an image receiving layer which contains substances which react with the developer substance to yield dyes. The developer substance in the unexposed areas of the light sensitive layer is transferred by the heat to the image receiving layer, so that a colored image is produced in these areas of the receiving layer.

One disadvantage of these known heat development or developer sublimation processes is the insufiicient stability in storage of the silver halide emulsion layers which contain developer. This instability is due to the fact that these layers contain substances which increase the residual 3,764,322 Patented Oct. 9, 1973 moisture of the layers, e.g. salts which form hydrates, or glycols, and is also due to the increased sensitivity to oxidation of most developer substances in these emulsion layers which are unhardened or are only slightly hardened and have a high residual moisture content.

A process which belongs to this type of copying process is described in US. Pat. No. 3,094,417. In this process, light sensitive layers which contain a transferable compound and a dye are used. The transferable compound (4-methoxy-1-naphthol) is converted into a nontransferable product on exposure to light, but is transferred from the unexposed areas into an image receiving layer by subsequent heating. In this image receiving layer, it reacts with a silver salt (silver behenate) to produce a colored positive image.

The last mentioned process has the disadvantage that the sensitivity of the layers is relatively slight and the keeping quality of the material is limited.

It is the object of the present invention to provide photographic dry copying processes and light sensitive materials suitable for these processes, which materials have sufiicient sensitivity to light and stability and contain dyes which render the material sensitive to the spectral range required and which enable multicolored and black and white images to be produced.

We now have found a process for the production of copies by imagewise exposure of a light sensitive layer which contains a sensitizer and an image producing compound which is transferable to an image receiving layer, the image producing compound in the exposed areas being converted into a nontransferable compound and the exposed layer being brought into contact with an image receiving layer which contains compounds which react with the image producing compound to form colored compounds, and the layers in contact with each other being heated to a temperature at which the image producing compound from the unexposed areas of the light sensitive layer is transferred to the image receiving layer, in which process the image producing transferable compound is a reducing agent transferable at a temperature of between C. and 200 C. but converted by exposure into non-volatile reaction products, and the sensitizer is a merocyanine dye having the formula:

R4 @(Cae i t wherein R =(1) a saturated or unsaturated aliphatic group preferably containing up to 6 carbon atoms which may be substituted, e.g. with halogen such as chlorine, bromine or iodine or with phenyl, hydroxyl, amino, carboxyl, sulfo, sulfamino, sulfamoyl, carbamoyl, carboxyamino, carboxyalkyl, alkoxycarbonyl, sulfate or thiosulfato groups; (2) a cycloalkyl group such as cyclohexyl or (3) aryl, in particular a group of the phenyl series;

R and R taken together, may represent the ring members required to complete an isocyclic or heterocyclic ketomethylene ring, suitable rings being those commonly found in cyanine chemistry, for example those of the rhodanine series such as 3-ethylrhodanine, 3-allylrhodanine or 3-cyclohexyl rhodanine, those of the 2- thio-2,4-oxazolidinedione series such as 2-ethyl-2-thio- 2,4-oxazolidinedione, those of the thiohydantoin series such as 1,3 dimethyl 2 thio-hydantoin or l-methyl- 3 phenyl 2 thiohydantoin, those of the barbituric acid or thiobarbituric acid series such as 1,3-diethylthiobarbituric acid or 1,3 diphenyl-thio barbituric 3 acid, those of the isoxazolone, oxindole, 2-thio-2,5- thiazolidine dione or 2,4 imidazolidinedione series, or the ketomethylene compounds characterized by the following structural formulae:

R =a hydrogen atom, an alkyl group having up to 4 carbon atoms, hydroxyl, alkoxy having up to 4 carbon atoms such as methoxy or ethoxy, or aryl such as phenyl;

R =(1) a saturated or unsaturated aliphatic group having preferably up to 6 carbon atoms which may be substituted, e.g. with phenyl, hydroxyl, halogen such as chlorine, bromine or iodine, with amino, carboxyl, sulfo or (2) aryl such as phenyl or naphthyl;

X=oxygen or sulfur;

n=0, 1, or 2;

Q=the members required to complete a S-membered or 6-membered heterocyclic group which may contain a condensed benzene or naphthalene ring and further substituents. Suitable heterocyclic groups are those customarily found in cyanine chemistry, for example those of the thiazole series (e.g. thiazole, 4 methylthiazole, S-methylthiazole, 4,5 dimethylthiazole, 4-phenylthiazole, 5-phenylthiazole, 4,5-diphenylthiazole, benzothiazole, 4-chlorobenzothiazole S-chlorobenzothiazole, 6- chlorobenzothiazole, 7-chlorobenzothiazole, 6-bromobenzothiazole, 5 iodobenzothiazole, 6-iodobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole, 6- methylbenzothiazole, 5,6 dimethylbenzothiazole, 4- phenylbenzothiazole, 5-pheny1benzothiazo1e, 6-phenylbenzothiazole, S hydroxybenzothiazole, 6 hydroxybenzothiazole, 4 methoxybenzothiazole, 5 methoxybenzothiazole, fi-methoxybenzothiazole, S-ethoxybenzothiazole, 6-ethoxybenzothiazole, 5,6-dimethoxybenzothiazole, 5,G-methylene-dioxybenzothiazole, S-diethylaminobenzothiazole, 6 diethylaminobenzothiazole, 5-

carboxybenzothiazole, 5-su1phobenzothiazole, tetrahyhydrobenzothiazole, 7 oxotetrahydrobe'nzothiazole, naphtho[ 1,2-d] thiazole, naphtho[2,1-d] thiazole, S-methoxynaphtho[2,1-d]thiazole, 5 ethoxynaphtho[2,1-d] thiazole, 7 methoxynaphtho[2,l d]thiazole, 8- methoxynaphtho[1,2 d]thiazole, etc.), those of the selenazole series, (e.g. 4 methylselenazole, 4-phenylselenazole, benz'oselenazole, 5 chlorobenzoselenazole, 5,6 dimethylbenzoselenazole, 5 hydroxybenzoselenazole, 5 methoxybenzoselenazole, tetrahydrobenzoselenazole, naphtho[1,2 d]selenazole or naphtho- [2,1 d]selenazole), those of the oxazole series (e.g. oxazole, 4 methyloxazole, 4 phenyloxazole, 4,5-diphenyloxazole, benzoxazole, 5 chlorobenzoxazole, 6- chlorobenzoxazole, 5,6 dimethylbenzoxazole, 5- phenylbenzoxazole, 5 hydroxybenzoxazole, 5- methoxybenzoxazole, 5 ethoxybenzoxazole, 6 dialkylaminobenzoxazole, 5 carboxybenzoxazole, 5 sul phobenzoxazole, 5 sulphonamidobenzoxazole, 5 )8- carboxyvinylbenzoxazole, naphtho[1,2 d] oxazole, naphtho[2,1 d] oxazole or naphtho [2,3 d]oxazole), those of the imidazole series (e.g. 1 methylimidazole, 1 ethyl 4 phenylimidazole, 1 butyl 4,5-dimethylimidazole, 1 methylbenzimidazole, 1 butyl-4-methylbenzimidaz'ole, 1 ethyl 5,6 dichlorobenzimidazole, 1 ethyl 5 trifluoromethylbenzimidazole, l-methyl- 4 naphtho[1,2 d]imidazole or 1 ethylnaphtho[2,3-d] imidazole), those of the 3,3 dialkylindolenine series (e.g. 3,3 dimethylindolenine, 3,3,5 trimethylindolenine, 3,3 dimethyl 5 methoxyindolenine, etc.), those of the pyridine series (e.g. pyridine, 3 methylpyridine, 4 methylpyridiue, 6 methylpyridine, 3,4- dimethylpyridine, 3,5 dimethylpyridine, 3,6 dimethylpyridine, 4,6 dimethylpyridine, 4 chloropyridine, 5 chloropyridine, 6 chloropyridine, 3 hydroxypyridine, 4 hydroxypyridine, 6 hydroxypyridine, 3- phenylpyridine, 4 phenylpyridine, 2,3 dimethylpyridine, 2,6 dimethylpyridine, 2 hydroxypyridine, quinoline, 3 methylquinoline, 5 methylquinoline, 7- methylquinoline, 8 methylquinoline, 6 chloroquineline, 8 chloroquinoline, 6 methoxyquinoline, 6- ethoxyquinoline, 6 hydroxyquinoline, 8 hydroxyquinoline, 5 0x0 5,6,7,8 tetrahydroquinoline, isoquinoline or 3,4 dihydroxyisoquinoline), those of the thiazoline series (e.g. thiazoline, 4 methylthiazoline, etc.) and those of the pyrroline, tetrahydropyridine, thiadiazole, oxadiazole, pyrimidine, triazine or benzothiazine series. The heterocyclic rings may carry any substituents, eig they may be substituted with other alkyl groups preferably containing up to 3flcarbon atoms, such as methyl or ethyl, with halogen such as chlorine, iodine or bromine, with trifluoromethyl or hydroxyl or with alkoxy having preferably up to 3 carbon atoms such as methoxy or ethoxy, with hydroxyalkyl, alkylthio or aryl such as phenyl or aralkyl such as benzyl or amino or substituted amino and the like.

[N alkylbenzothiazole]-dimethine[1,3 dialkylthiobarbituric acid]merocyanines are examples of suitable compounds and the following are more specific examples:

Jam

L 1; Q =c 1.14mi!) 0, g (I:

o II N s a 1130 o y N S HsCzOOCGH=CH S HBC N O (EH3 N no 0 c-on=on S V S l N l H30 O:

CoHs

The merocyanines according to the invention may be prepared by known methods (see F. M. Hamer The Cyanine Dyes and Related Compounds (1964). Preparation of the open chain cyanothioacetamide merocyanines has been described in British patent specification No. 1,219,330.

The image-producing compounds must meet the following conditions:

(1) They must react in the presence of the sensitizers defined above upon exposure to form non-transferable reaction products.

(2) They must be transferable at temperatures of between and 200 C. to the image receiving layer.

(3) They must be capable of reacting with the compounds of the image receiving layer to form colored reaction products.

The following reducing agents, for example are particularly suitable image-producing compounds:

(1) Phenols and naphthols, especially benzene compounds of the naphthalene series containing at least two aromatic hydroxyl groups which may be partly etherified such as 1-hydroxy-4-alkoxy-naphthalenes, or which are substituted with a hydroxyl group and an amino or substituted amino group, substituted being in the paraor ortho-position in the case of benzene derivatives. Examples of such compounds are listed in Table 1 below.

TABLE 1 1-hydroxy-4-methoxynaphthalene,

1-hydroxy-4-ethoxynaphthalene,

1-hydroxy-2-methy1-4-methoxynaphthalene,

4,4'-dimethoxynaphtha1ene-1, 1-dihydroxy-2,2-

binaphthyl,

1,4-dihydroxynaphtha1ene,

1-hydroxy-4-aminonaphthalene,

1,2,3-trihydroxy-5-acetylbenzene,

methyl 3,4,5-trihydroxybenzoate,

ethyl 3,4,5-trihydroxybenzoate,

1,2,3,4-tetrahydro-8-hydroxyquinoline,

1-(2'-methylsulphonamidoethyl)-1,2,3,4-tetrahydro-6- hydroxyquinoline,

4-methylaminophenol,

4-isopropylideneaminophenol,

4-aminophenol,

4-hydroxyanilinomethanesulfonic acid,

9 4-hydroxy-3-methylanilinomethanephosphonic acid, 1-hydroxy-4-propoxynaphthalene.

Also suitable as image-producing compounds are the aminophenol developers described in German patent specifications 1,159,758, 1,200,679, 1,203,129 and 1,203,- 605.

(2) Pyrazolidone-(3) derivatives of the following formula:

R represents hydrogen, alkyl or aryl which may be substituted for example with lower alkyl or alkoxy groups or with halogen such as chlorine, bromine, or iodine, and

R R R and R represent hydrogen, alkyl, aryl or a substituted alkyl or aryl group.

The compounds listed in the following table have been found to be suitable.

TABLE 2 l-phenyl-S-pyrazolidone, 1-m-tolyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone, 1-phenyl-4-methyl-3-pyrazolidone, l-phenyl-S-methyl-3-pyrazolidone, 1,4-dimethyl-S-pyrazolidone,

4-methyl-3 -pyr azolidone,

4,4-dimethyl-3 -pyrazolidone, 1-phenyl-4,4dimethyl-3 -pyrazolidone,

1- (m-chlorophenyl) -4-methyl-3-pyrazolidone, 1- (p-chlorophenyl) -4-methyl-3-pyrazolidone, 1- (m-chlorophenyl) -3-pyrazolidone,

1- (p-chlorophenyl) -3 -pyrazolidone,

1- (p-tolyl) -4-methyl-3-pyrazolidone,

1- (o-tolyl) -4-methyl-3-pyrazolidone,

1- (p-tolyl) -3-pyrazolidone,

1- (m-tolyl) -3-pyrazolidone,

l- (m-tolyl) -4,4-dimethyl-3-pyrazolidone,

l- (2'-trifiuoroethyl -4,4-dimethyl-3-pyrazolidone, S-methyl-B-pyrazolidone.

The compounds listed above may be prepared by the processes described in British patent specification Nos. 679,677 and 679,678, the phenimines which may be obtained by reacting acrylonitrile derivatives with the corresponding hydrazine compounds being saponified to 3-pyrazolidones.

3-pyrazolidones may also be prepared by the process described in British patent specification No. 703,669, the end products being obtained by direct condensation of esters of acrylic acid or derivatives thereof with hydrazines. This process is particularly suitable for reactions with hydrazine itself. The 3-pyrazolidones obtained in this way which have an oily consistency can be obtained as crystalline compounds by converting them into salts, e.g. hydrochlorides, sulfates, or 1,5-naphthalene disulfonates. The preparation of 4,4-dialkyl-3-pyrazolidones has been described in US. Pat. 2,772,282. In the process described there, 2,2-dialkyl-fl-chloropropionic acid chlorides are reacted with hydrazines.

The 3-pyrazolidones may be used as free bases or in the form of their salts.

3) N,N-dialkylphenylenediamine derivatives, especially those in which the alkyl groups contain up to 3 carbon atoms and the phenylene nucleus may be substituted with alkyl or alkoxy groups.

The free primary amino groups may be blocked, for example in the form of a Schiifs base by reaction with aldehyde, especially benzaldehyde, or with a sulfomethyl group which may be introduced by a Mannich reaction. Phenylenediamine derivatives which have a blocked primary amino group are particularly suitable because stable layers can easily be prepared with such compounds.

The compounds listed in the following table have been found to be suitable.

TABLE 3 N,N-diethyl-p-phenylenediaminesulfate, N,N'-dibenzylidene-p-phenylenediamine, N,N-diethyl-N'-sulfomethyl-p-phenylenediamine, N,N-dimethyl-N'-sulfomethyl-p-phenylenediamine, 3-methyl-4-sulfomethylamino-N,N-diethylaniline N-benzylidene-N',N'-diethyl-p-phenylenedimaine, 3-methoxy-4-sulfomethylamino-N,N-diethylaniline.

The image producing substances of the above mentioned type are known per se. Methods of their preparation may be found in German patent specification Nos. 1,159,758 and 1,203,129, and in the literature.

(4) Pyrazolin-S-one derivatives: Those pyrazolin-S-one derivatives which contain at least one hydrogen in the 4-position or a 4-aminophenyl-amino group are preferred, such as those of the formula:

wherein R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group preferably containing up to 6 carbon atoms which may be substituted, e.g. with phenyl as in the benzyl group, with cyano, with halogen, e.g. fluorine, with amino in which case the amino group may itself be substituted, e.g. alkylated amino groups, especially dialkylamino, the alkyl groups in the alkylamino group preferably containing up to 3 carbon atoms, (3) aryl, especially a group of the phenyl series, the aryl ring being itself optionally substituted, e.g. with alkyl or alkoxy preferably containing up to 3 carbon atoms, with nitro, halogen such as fluorine, chlorine or bromine, with amino or substituted amino groups, e.g. alkylated amino groups, (4) a heterocyclic group, e.g. benzothiazolyl or (5) cycloalkyl such as cyclohexyl or cyclopentyl;

R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group preferably containing up to 6 carbon atoms, the aliphatic group optionally carrying further substituents, e.g. phenyl as in the case of a benzyl or phenylethyl, halogen such as fluorine, chlorine or bromine, alkoxycarbonyl, hydroxyl or alkoxy, (3) aryl, especially a group of the phenyl series, the aryl ring being optionally itself substituted, e.g. with alkyl or alkoxy having preferably up to 3 carbon atoms, or with nitro or halogen such as chorine or bromine, (4) a heterocyclic group, e.g. pyridyl, (5) cycloalkyl such as cyclohexyl or cyclopentyl, (6) hydroxyl which may be etherified, especially with short chained aliphatic radicals having up to 3 carbon atoms, (7) amino which may be substituted, e.g. with akyl, preferably having up to 3 carbon atoms, or (8) alkoxycarbonyl having up to 5 carbon atoms;

R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group having preferably up to 6 carbon atoms which may be substituted, e.g. with phenyl as in the case of benzyl or phenylethyl groups, or With halogen such as chlorine or bromine, nitrile, alkoxy, alkoxycarbonyl or anilinocarbonyl, (3) aryl,

1 1 especially a group of the phenyl series, in which the polyvinyl chloride, copolymers of vinyl chloride and vinyl aryl ring may itself be substituted, e.g. with alkyl or acetate, polyvinyl acetate or completely or partly saponialkoxy having preferably up to 3 carbon atoms, nitro fied polyvinyl acetate or copolymers of vinyl acetate, for or nitrile, (4) amino in which the amino groups may example with olefines such as ethylene or propylene and be substituted, e.g. with alkyl having preferably up to copolymers of monomers of acrylic or methacrylic acid 3 carbon atoms, cycloalkyl, phenyl or acyl, especially or derivatives thereof such as esters, amides of nitriles,

acyl groups of short chained aliphatic carboxylic acid, etc. The light sensitive layers may be used as self-support- (S) alkoxy having preferably up to 3 carbon atoms; ing layers or applied to a support. Suitable supports are R =hydrogen or a 4-aminophenylamino group or 4-die.g. paper, especially baryta-coated or polyolefine-coated, alkylaminophenylamino group. more particular polyethylene-coated paper and cellulose Furthermore, 13 and 14 may together represent the esters, e.g. cellulose triacetate, polyesters, especially those ring members required to complete a S-membered or 6- based on ethylene f p l glass, em

member-ed carbocyclic or heterocyclic in The image receiving materlal advantageously consists of uita l compounds are listed in the following table an image receiving layer applied to a suitable support. Sub- Where the first 33 compounds have 1-1 for R 15 stantially the same substances as those described above TABLE 4.

Pyrazolin-5-one No. R" R" R14 a om.

4. Cyclohexyl Cs 5 H. CHzCOOC2H5---- H. Pyridyl-4- H- CH1 H. H. H. a dim th 1 h 1 ,5- e y eny CsHx p H. 3-nitrophenyl 3-aminopl1enyl CH3. B-nitrophenyl- Benzyl Z-ethoxyphenyl CH:. 5 5---- CH3. CsH5 C2115. CnHs CHzCH2 H2CONHCsH5.

.. CsHs.. CH3 CH3.

l-[benzothiazolyl-2']-3, i-dimethyli-ld-diethylaminophenylamiuo]-pyrazolin5-one 1-phenyl-3,4-dimethylA-[p-diethylaminophenylamino]-pyrazolln-5-one The pyrazolin-S-one derivatives are prepared by methfor the light sensitive material are suitable as binding ods known from the literature. Reference may be made agent for the image receiving layer or as the layer supe.g. to the monograph by R. H. Wiley Pyrazolones, port.

Pyrazolidones and Derivatives (1964) and German pat- When choosing a binder for the light sensitive layer and cut specification No. 1,155,675. the image receiving layer, care should be taken to ensure The light sensitive layers contain at least one of the that the layers will not stick at elevated temperature. These sensitizers in quantities of 10 to 300 mg./m. and one or diificulties, however, are well-known from other transfer more image producing compounds in quantities of 0.02 processes, e.g. the silver salt diffusion process or heat deto 0.5 g./m. This range of concentration has been velopment processes, and can easily be solved by making found to be suitable although amounts outside this range use of the experience gained in these known fields. may, of course, be employed. The concentration depends The image receiving layer contains compounds which mainly 011 the requirements of a Particular l'fipfodllcthm should be insensitive, or as restricted as possible in their process. sensitivity, to visible light under the conditions of the proc- Particularly suitable combinations Of sensitizers with egg of the invention, and which react with the transferred the image producing reducing agents can be determined image producing compounds to form colored products. by simple tests. Suitable tests for this purpose will be Numerous compounds have been found suitable for this described hereinafter. The choice of solvent and of the purpose. Chemically, these compounds belong to a Wide binding agent used for producing the light sensitive layer variety of classes so that their systematic chemical clasis also important for obtaining optimum results. Comsification is not possible. However, suitable compounds or binations of components particularly suitable for any suitable combinations of an image producing compound given purpose can be determined by the usual tests known arranged in the light sensitive layer and of the reactant to the ordinary skillled person. for the image forming reaction in the image receiving T P p the light Sensitivfi y the Sensifilers and layer can be sufficiently clearly defined by simple laboraimase producing compound y be suspended or dissolved tory tests customarily employed in the art. Thus, for exin solvents and mixed with a binding agent and applied ample, the two reactants must react when briefly heated in this form to the layer support. for a few seconds to a temperature of between about 80 The usual natural or synthetic film-forming polymers are and 200 C. to form a stable dye. A second test must then suitable as binding agents for the light sensitive layer, e.g. be carried out to choose suitable image producing comproteins, especially gelatin, cellulose derivatives, especialpounds. The purpose of this test is to show Whether the ly cellulose ethers, cellulose esters or carboxymethyl celluimage producing compound will react sufi'lciently rapidly lose, alginic acid and its derivatives, starch ether or galin the presence of the merocyanine dye on exposure to lactomannane, polyvinyl alcohol, polyvinyl pyrrolidone, light, so that, when the mixture is heated after it has been exposed, it will not produce a colored compound with the reactant in the image receiving layer.

The following classes of compounds are examples of suitable compounds in the image receiving layer for reaction with the image producing compound transferred from the light sensitive layer.

(1) Heavy metal compounds, especially compounds of metals of Groups IIIa to Va and Groups lb, IIb and VIb and VIII of the Periodic Table, e.g. compounds of the following heavy metals: cadmium, mercury, iron, cobalt, nickel, copper, silver, gold, bismuth or thallium. Salts of these metals with long chained aliphatic, carboxylic acids are especially suitable e.g. nickel stearate, cobalt palmitate, iron stearate, and the addition compound of bismuth nitrate with amines such as triethanolamine. It is found to be especially suitable to use silver compounds which are substantially insensitive to light under the conditions of the copying process according to the invention, e.g. the silver salts described in US. Pat. No. 3,330,663, i.e. silver salts of aliphatic carboxylic acids having a thioether group or silver salts of long-chained fatty acids such as silver behenate, silver palmitate or silver stearate, etc. containing 8 to 24 carbon atoms. When the above-mentioned heavy metal compounds are used, brown to black copies are obtained. The image consists of the particular metal and/or a reaction product of transferred image producing compound.

(2) The image receiving layer may also contain oxidizing agents and dye components which react imagewise with the transferred image producing compound by oxidative coupling to form dyes, e.g. the known color couplers of color photography which couple with oxidized phenylene diamine derivatives to produce dyes, or compounds which when in their oxidized form react under oxidizing conditions e.g. with pyrazolin-S-one compounds to yield colored coupling products. Suitable reactants for these reactions are e.g. oxidation products of p-phenylene diamines or their derivatives which react with pyrazolin-S- one compounds to form the azomethine dyes known in conventional color photography.

(3) Diazonium salts which react with the transferred reducing agent, e.g. with aminophenols, aminonaphthols, phenylenediamine derivatives or pyrazolin-S-one compounds, to form a colored product. This reaction is similar in principle to the one employed in the known photographic diazo type process.

(4) Leucophthalocyanines are also suitable for use as reactants for the reaction which produces the image dye. Leucophthalocyanines which have not or could not be prepared from finished phthalocyanines are known as phthalocyanine precursors. This term is used, for example, in the article by B. R. A. Brooks, J. G. Burt, B. F. Skiles and M. S. Whelen, J. Org. Chem. 24, page 383 (1959). In the relevant chapter in Ullmanns Encykopadie der Technischen Chemie, 3rd edition, volume 13, the term phthalocyano-metal complexes is used for the same type of materials for which in the present context the term leucophthalocyanines is used. The last mentioned expression is explained e.g. in US. Pat. No. 2,772,285. Although that patent refers only to leuco copper phthalocyanine, its explanation is also applicable analogously to the corresponding complexes with other metals which form phthalocyanines. Leucophthalocyanines according to this definition are colorless or only slightly colored products in which the phthalocyanine structure is already completely formed, and which can be converted into phthalocyanines by a reduction process. In this reduction process, constituents which the leucophthalocyanine molecule contains in addition to phthalocyanine may also be split off. Such leucophthalocyanines may be prepared e.g. by first preparing a phthalocyanine, e.g. a phthalocyanine which is free from metal or CuPc (Pc=phthalocyanine), NiPc, Co'P'c or ZnPc and then treating the phthalocyanine with additional ligands under oxidizing conditions, or by heating a reaction mixture which is in itself suitable for the preparation 14 of a phthalocyanine to a temperature slightly below that required for the preparation of the phthalocyanine, or by carrying out the reaction without the reduction potential required for formation of the phthalocyanine.

Leucophthalocyanine which contain metal are more suitable for this reaction because those which are free from metal are relatively unstable. The highly stable and only slightly colored leuco cobalt phthalocyanines are especially suitable.

Especially to be mentioned are the leuco cobalt phthalocyanines which are described in Angewandte Chemie, 68, page 145 (1956), e.g. the phthalocyanine cobalt ethylene diamine complex.

Instead of ethylene diamine, other diamines or polyamine may also be used as ligands, for example propylene diamine-(1,2), and -(1,3), monoethylpropylene diamine (1,3), hydroxyethylethylene diamine, N-methyl-N-fl-hydroxyethylpropylene diamine, N,N'-diethylethylene diamine, N,N-di-(B-aminoethyD-ethylene diamine, N,N'-di- (B-aminoethyD-ethylene diamine or N,N-di-[/3-(/3-aminoethyl)-aminoethyl]-amine or also monoamines such as 3- (2-ethylhexyloxy)-propylamine-(1) or stearylamine. The solubility properties of the leuco-CoPc depend on the type of amine used in the molecule.

In another embodiment of the process of the present invention, reactants can be completely omitted from the image-receiving layer. This applies e.g. to image producing compounds for example phenols or naphthols which yield sufliciently colored compounds when heated alone or in the presence of atmospheric oxygen. In this case, plain, uncoated paper may be used as image receiving material.

In addition to the image producing reactants properly speaking, the image receiving layers may contain other additives which advantageously influence the color tone, contrast, stability, etc., of the copy. Image receiving layers of this type are already known and have been described, for example, in German auslegeschrift Nos. 895,101; 1,003,577; 1,159,758; 1,004,043 and 1,165,410, in Dutch patent specification No. 277,086, in US. Pat. 3,335,006 and in Belgian patent specification Nos. 614,064 and 609,- 057.

The image receiving layers may also contain white pigments, e.g. zinc oxide, silicon oxide or titanium dioxide as fillers, for improving the whites and for controlling the tendency of the layers to stick, and they may contain terpene resins and organic acids for improving the stability in storage. Image receiving layers of this type have been described in US. Pat. Nos. 3,074,809 and 3,107,- 174.

The color tone of the images produced can be altered e.g. with compounds of the 1-(2H)-phthalazinone series. Toners of this type have been described in US. Pat. Nos. 3,080,254 and 3,446,648. Additives which accelerate the reduction reaction in the image receiving layer have also been found to be advantageous. Suitable compounds for this purpose are e.g. sterically hindered phenols such as 2,6-di-tertiary butyl-p-cresol. Compounds of this type have been described in US. Pat. 3,218,166. Furthermore, the image tone and image density can be improved with certain metal salts, e.g. copper-II stearate. Metal ion image intensifiers and their application have been described in German auslegeschrift No. 1,572,209.

The usual sources of light used in reproduction work, such as mercury lamps, iodine quartz lamps or incandescent lamps, may be used for exposing the light sensitive layers according to the invention. The spectral sensitivity of the light sensitive material depends on the nature of the dye used or the combination of dye and reducing image producing compound.

Exposure may be carried out either in contact or optically or by reflection.

Transfer of the image producing compounds from the unexposed areas of the light sensitive layers to the image receiving layer is carried out by heating at temperatures of between and 200 C. Heating may be effected e.g.

15 by passing the exposed light sensitive layer in contact with the image receiving layer over hot plates or rollers or by irradiation with infra-red light. The most advantageous temperature and heating time depend, of course, on the nature of the image producing compound and can be determined by a few simple tests.

According to one variation of the material according to the invention, the image receiving layer and the light sensitive layer may be combined on one support. In this case, it is necessary to use a transparent support on which the image receiving layer, e.g. a layer containing silver behenate dispersed in a copolymer of styrene and isobutylene, is applied first, and the light sensitive layer, e.g. an ethylcellulose layer containing the sensitizer and reducing compound, is applied on the image receiving layer.

The sensitivity of these light sensitive layers may advantageously be increased or extended to other spectral regions to an extent depending on the absorption of the compounds according to the invention by combining the dyes used according to the invention with photoreducible dyes, e.g. those mentioned in US. Pat. 3,094,417, such as erythrosine.

EXAMPLE 1 Light sensitive material The following casting solution is applied to a layer support of glassine paper:

30 mg. of dye No. 28,

50 mg. of 1-hydroxy-4-methoxynaphthalene,

2.5 g. of ethyl cellulose as a 5% solution in butanone-2 and 150 ml. of butanone-Z.

The layer is dried in the usual manner. The image receiving layer is prepared by grinding the following components for 6 hours in a ball mill:

2.1 g. of a mixture of 1 mol silver behenate and 1 mol behenic acid,

1.66 g. of terpene resin,

0.86 g. of 1-(2H)-phthalazinone,

4.8 g. of zinc oxide,

0.56 g. of silica gel,

0.37 g. of 2,6-di-tert.butyl-4-methylphenol,

0.034 g. of tetrachlorophthalic acid anhydride,

15 g. of an 8% ethylmethacrylate solution in pentanone-3,

80 g. of a 1.5% polyvinyl acetate solution in butyl acetate,

and

30 g. of butylacetate,

and applying the resulting mixture to paper and drying. When dry, the layer contains about 0.2 of silver per rn. in the form of silver behenate.

Processing The light sensitive material is exposed behind a 2 step Wedge to a 1000 watt iodine quartz lamp from a distance of 30 cm. for 5 minutes.

The exposed layer is then brought into contact with the image receiving layer and heated to a temperature of 125 C. for 10 seconds or treated in an ordinary commercial heat development apparatus.

The results are listed in Table 5 below along with those obtained using the other dyes instead of dye No. 28.

16 TABLE 5Continued Dye No Steps /2 11 6 EXAMPLE 2 Light sensitive material The following casting solution is applied to a layer support of glassine paper:

30 mg. of dye N0. 27

50 mg. of l-hydroxy-4-methoxynaphthalene, 2.5 g. of ethylcellulose 150 ml. of ethyl acetate.

The layer is dried in the usual manner.

Processing The light sensitive matrial is exposed through a positive transparent original to a 1000 watt normal incandescent lamp (tungsten filament) at a distance of 5 to 10 cm. for 30 seconds.

Instead of a transparent original, a text printed on ordinary paper may be used. The exposure to reflected light required in this case takes 15 to 25 seconds under other- Wise the same conditions.

The exposed layer is then brought into contact with the image receiving layer described in Example 1 and the layers are heated to a temperature of to C. for 5 to 20 seconds or treated in an ordinary commercial heat development apparatus.

A sharp, positive black copy of the original is obtained.

Other combinations may be used instead of dye No. 27 and instead of the image producing compound mentioned above. The results are summarized in Table 6 below.

TABLE 6 Dye I Quantity Color of the N 0. Image producing compound in mg. copy 16. l-hydroxy-5methoxynaphthalene 50 Grey black. 29 Compound 8 of Table 4 100 Do. 16- Compound 33 of Table 4 100 D0. 1... Compound 26 of Table 4.-. 100 D0. 28- Compound 20 of Table 4 100 D0.

.. 1,2,3, i-tetra.l1ydro-8-hydroxy- 50 Black brown.-

qmnolme. 1- 1-phenyl-3-pyrazolidone 50 Dark brown. 1- 1-phenyl-5-methyl-3-pyrazo1idone.. 50 Black brown.

doe 50 Do. 29- do- 50 Do. 1 N -benzylidene-N,Ndiethyl-p 50 Brown.

phenylenediamine.

EXAMPLE 3 Light sensitive material A light sensitive layer is prepared from a solution of 30 mg. of dye No. l,

100 mg. of N,N-diethyl-N-sulfomethyl-p-phenylenediamine,

100 mg. of sodium acetate,

100 ml. of ethanol, and

50 ml. of a 1.5% solution of a cellulose ether in ethanol by casting the solution on paper and drying.

Image receiving material A layer is prepared from a solution 1.5 g. of 1-phenyl-3-methylpyrazolone-(5), 1 g. of sodium bromate,

35 ml. of water and 15 ml. of a 5% aqueous polyvinyl alcohol solution,

by casting the solution on paper and drying.

Processing Processing is carried out as in Example 2. A red posi- Image receiving material A layer cast on a paper support is prepared from 150 mg. of N,N-diethyl-p-aminophenyl-diazonium chloride zinc chloride complex,

ml. of water and 5 ml. of a 1.5% aqueous solution of a cellulose ether.

Processing Processing is carried out as in Example 2. A brown positive is obtained.

EXAMPLE 5 Light sensitive material A light sensitive layer is prepared from a solution of 30 mg. of dye No. 29, 100 mg. of 1-phenyl-3-methyl-pyrazolin-5-one, 2.5 g. of ethylcellulose and 150 ml. of ethyl acetate.

The solution is applied to a layer support of glassine paper and dried in the usual manner.

Image receiving layer The following casting solution is applied to a layer support of baryta paper:

5 g. of 4-dimethylaminobenzene diazonium tetrafiuoborate,

1 g. of saponin,

1 g. of polyoxyethylenehydroxyethylcellulose and 100 ml. of water.

Processing Processing is carried out as described in Example 2. A positive red image of the original on a grey background is obtained.

EXAMPLE 6 Light sensitive material as in Example 1.

Image receiving material 50 mg. of a leuco cobalt phthalocyanine stearylamine complex prepared by the method described below are dissolved in 40 g. of a 1.5% polyvinylacetate solution in acetone and 26 g. of a 4% cellulose acetate solution in acetone, and the solution is cast on paper and dried.

Processing Process is carried out as described in Example 2. A blue positive of the original is obtained.

The leuco CoPc used was prepared as follows:

50 g. of a crude product prepared according to Example 1 of German patent specification No. 855,710 were converted into the nitrate by treatment with concentrated nitric acid as described in German patent specification No. 839,939. 16 g. of the dried nitrate were boiled in 50 ml. of cleaning petrol with 15 g. of stearylamine for 20 minutes, the mixture was diluted with 750 ml. of cleaning petrol, the resulting solution was filtered at C. and stirred cold for several hours and the product which crystallized was removed by suction filtration and dried. The filtered off reaction product, of which 27 g. were obtained, was dissolved in boiling ethanol, the solution was stirred cold and the crystalline product was removed by suction filtration and dried. 12 g. of an orange coloured substance were obtained.

Instead of 1-hydroxy-4-methoxynaphthalene, 50 mg. of 1-phenyl-5-methyl-3-pyrazolidone may be used as image producing compound with the same result.

EXAMPLE 7 Light sensitive material as in Example 1.

Image receiving material An image receiving material is prepared from 5 g. of iron(II-I) chloride, 2 g. of nitrilotriacetic acid and 30 ml. of a 5% aqueous solution of polyvinyl alcohol. The solution is neutralized with ammonia and cast on paper.

Processing is carried out as described in Example 2. A cyan positive is obtained.

EXAMPLE 8 Light sensitive material as in Example 1.

Image receiving material 1 g. of bismuth nitrate is shaken for 6 hours in a ball mill with 40 g. of a 1.5% solution of polyvinyl acetate in acetone and 26 g. of a 4% solution of acetylcellulose in acetone.

The mixture is cast on paper and dried.

Processing Processing is carried out as described in Example 2. A brown positive is obtained. Instead of bismuth nitrate,

0.6 g. of thallium(I) chloride or 0.8 g. of mercury(II) bromide may be used with equal success in the image receiving layer.

EXAMPLE 9 Light sensitive material as in Example 1. Processing is carried out as described in Example 2, but the image receiving material used is ordinary writing paper. A positive cyan image of the original is obtained.

EXAMPLE 10 Light sensitive material as in Example 1.

Image receiving material Ammonia is added to a solution of 5 g. of copperfll) chloride in 75 ml. of H until the precipitate which forms redissolves, and 30 ml. of aqueous polyvinyl alcohol are then added and the solution is cast on paper and dried.

Processing is carried out as described in Example 2. A grey green positive image of the original is obtained.

EXAMPLE 11 When used in combination with other dyes, e.g. erythrosine which has its sensitivity at 540 mm., the dyes listed in the following table extend the sensitivity of the light sensitive material to the blue or red region of the spectrum.

Light sensitive material The following casting solution is applied to a layer support of polyethylene terephthalate and dried:

30 mg. of erythrosine,

30 mg. of a dye shown in Table 7 below,

50 mg. of 1-hydroxy-4-methoxynaphthalene, 2.5 g. of ethylcellulose and 150 ml. of ethyl acetate.

Processing A set of interference filters was used to determine the spectral sensitivity of the light sensitive material. The filters are permeable to the following wavelengths: 350 nm., 390 nm., 405 nm., 435 nm., 480 nm., 505 nm., 515 nm., 540 nm., 550 nm., 570 nm., 590 nm., 605 nm.

The light sensitive material is exposed behind the interference filters to a 1000 watt iodine quartz lamp from a distance of 30 cm. for a time varying between 5 and 30 minutes according to the dye used. The exposed material is then brought into contact with the image receiving layer described in Example 1 and processed in an ordinary commercial heat development apparatus.

TABLE 7 Sensitivity at the following Dye No.: wavelengths Erythrodine- 540 nm.

EXAMPLE 12 Light sensitive material The following casting solution is applied to a layer support of polyethyleneterephthalate and dried:

30 mg. of erythrosine,

30 mg. of a dye as shown in Table 8 below, 50 mg. of 1-hydroxy-4-methoxynaphtha1ene, 2.5 g. of ethylcellulose and 15 0 ml. of ethylacetate.

Processing is carried out as described in Example 1. A higher sensitivity is obtained by combining the two dyes, as indicated by the step numbers shown in Table 8 below.

TABLE 8 Dye: Steps {/5 Erythrosine alone 7 With dye 1 10 With dye 11 With dye 16 12 We claim:

1. In the process for the production of an image by (a) imagewise exposing a light-sensitive layer which contains a sensitizer sensitizing the layer to light and an image-producing compound transferrable to an imagereceiving layer at temperatures between to 200 C. the image-producing compound in the exposed areas being converted in the presence of the sensitizer into a non-transferrable compound, and (b) transferring the unconverted image-producing compound to an imagereceiving layer and causing it to react in the image-receiving layer to form a colored product, the improvement according to which the sensitizer is at least one dye of the formula:

wherein 2. The combination according to claim 1, characterized in that Q is a benzothiazole ring.

3. The combination according to claim 1, characterized in that R and R form a thiobarbituric acid ring.

4. The combination according to claim 1, characterized in that the sensitizer is an [N-alkylbenzothiazole1- dimethine-[1,3-dialkylthiobarbituric acid] merocyanine.

5. The combinations according to claim 1, characterized in that the sensitizer is:

6. The combination according to claim 1, characterized in that the sensitizer is:

7. The combination according to claim 1, characterized in that the image producing compound is a l-hydroxy-4-alkoxynaphthalene.

8. The combination according to claim 7, characterized in that the image producing compound is l-hydroxy- 4-methoxynaphthalene.

9. The combination according to claim 1, characterized in that the image producing compound is 1,23,4- tetrahydro-S-hydroxyquinoline.

10. The combination according to claim 1, characterized in that the image producing compound is a 3- pyrazolidone.

11. The combination according to claim 10, characterized in that the image producing compound is 1- phenyl-4-methyl-3-pyrazolidone.

12. The combination according to claim 1, characterized in that the image producing compound is a pyrazolin-S-one compound of the following formula:

wherein R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group or (5) cycloalkyl;

R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group, (5) cycloalkyl, (6) hydroxyl, (7) amino or (8) an alkoxycarbonyl group;

R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) amino or (5) alkoxy; or R and R together represent the members required to complete a carbocyclic or heterocyclic ring; and

R =hydrogen or a 4-aminophenylamino group.

13. The combination according to claim 1, characterized in that the image receiving layer contains a heavy metal compound which is not sensitive to light under the conditions of the process.

14. The combination according to claim 13, characterized in that the heavy metal compound is a silver compound which has little or no sensitivity to light under the conditions of the process.

15. The combination according to claim 14, characterized in that the silver compound is a salt of a long chain aliphatic carboxylic acid having 8 to 24 carbon atoms.

16. The combination according to claim 14, characterized in that the silver compound is a salt of an aliphatic carboxylic acid substituted with a thioether group.

17. The combination according to claim 13, characterized in that the image receiving layer is used contains a toner.

18. The combination according to claim 13, characterized in that the image receiving layer contains a sterically hindered phenol that accelerates the reaction in the image-receiving layer.

19. The combination according to claim 13, characterized in that the image receiving layer contains a white pigment.

20. The combination according to claim 13, characterized in that the image receiving layer contains a metal ion image intensifier.

21. In a light-sensitive photographic layer containing a sensitizer sensitizing the layer to light and an imageproducing compound which can be transferred to an image-receiving layer at temperatures of between 80 and 200 C., but which is converted by exposure into nontransferrable reaction product in the presence of the sensitizer, the improvement wherein the sensitizer has the formula:

34 @(Cae )m t j R X \R3 wherein R =(1) a saturated or unsaturated aliphatic group, (2)

cyclo alkyl or (3) aryl; R =CN, COR CON(R 2 or COOR 22 R =R O'--R or N(R or R +R =the ring members required to complete an isocyclic or heterocyclic ketomethylene ring; R =hydrogen, alkyl having up to 4 carbon atoms, by-

droxyl, alkoxy having up to 4 carbon atoms or aryl; R =a saturated or unsaturated aliphatic group or aryl; X=oxygen or sulphur; n=0, 1 or 2; Q=the members required to complete a S-membered or 6-membered heterocyclic ring.

22. The combination according to claim 21, characterized in that Q is a benzothiazole ring.

23. The combination according to claim 21, characterized in that R and R form a thiobarbituric acid ring.

24. The combination according to claim 21, characterized in that the sensitizer is a [N-alkylbenzothiazole1- dimethine-[1,3-dialkyl-thiobarbituric acid] merocyanine.

25. The combination according to claim 21, characterized in that the sensitizer is the following sensitizer.

26. The combination according to claim 21, characterized in that the sensitizer is 27. The combination according to claim 21, characterized in that the image-producing compound is a 1 hydroxy-4-alkoxynaphthalene.

28. The combination according to claim 27, characterized in that the image-producing compounds is l-hydroxy-4-methoxynaphthalene.

29. The combination according to claim 23, characterized in that the image-producing compound is 1,2,3,4- tetrahydro-S-hydroxyquinoline.

30. The combination according to claim 24, characterized in that the image-producing compound is a 3-pyrazolidone.

31. The combination according to claim 30, character ized in that the image-producing compound l-phenyl- 4-methyl-3-pyrazolidone as image producing compound.

32. The combination according to claim 21, characterized in that the image producing compound is a pyrazolin-5-one compound of the formula:

wherein R =(1) hydrogen, (2) a saturated or olefinically unsaturated aliphatic group, (3) aryl, (4) a heterocyclic group or (5) cycloalkyl;

23 24 R =(1) hydrogen, (2) a saturated or olefinically un- References Cited saturated aliphatic group, (3) aryl, (4) a heterocyclic UNITED STATES PATENTS group, (5) cycloalkyl, (6) hydroxyl, (7) amino or 3,094,417 7/1963 Workman 96 76 R Y y P; 3,484,23 12 1969 O 9 29 R =(l) hydrogen, (2) a saturated or oiefinically un- 5 saturated aliphatic group, (3) aryl, (4) amino or (5) NORMAN G-TORCHIN, Primary EXamiIlel alkoxy; or R and R together represent the ring LLGOODROW, Assistant Examiner members required for completing a carbocyclic or heterocyclic ring; and 10 R =hydrogen or a 4-aminopheny1amino group. 11736.9; 96-441, 76 R, 3 

